I seem to have done everything to meet the requirements of this achievement to the point of acquiring the secret codes.
But I can’t seem to now get the final mission to get the achievement. I got all the way to Gargos and beat him without the opportunity to finish it off.
So now I have these secret codes and I get Stalker missions again and now have 4 more transceivers. Does the fact that I have the secret codes going into new playthrough mean I’m effectively locked out of getting the achievement?